Work feeding mechanism



July 31, 1934.

H. E. DICKERMAN WORK FEEDING MECHANISM 2 Sheets-Sheet 1 l Filed Jan. 23. 1935 llll :RX N u R.A S. ,WH H mm im Wm. #m

a HY B July 31, 1934. H E, mcKERMAN 1,968,479

WORK FEEDING MECHANISM 2 sheets-sheet `2 Filed Jan. 23. 1933 INVENTOR. Haan# /cm/v/w WM A TTOR EYS.

Patented July 31, 1934 UNITI-:D STATES PATENT OFFICE WORK FEEDING MECHANISM This invention relates to improvements in mechanism for feeding stock, usually in Wire or strip form, to the cooperating members of a machine, such for example as a punch press, by

` which members the stock is worked in any desired way, as by cutting, piercing, shaping and the like.

I-Ieretofore, so far as I am aware, such stock has been fed into the machine by mechanism such for l0 example as a roll feed, which is built into and forms a fixed part of the machine. In a punch press for example, there is a work feeding mechanism built into the machine and, whenever the cooperating work-forming members (known in the trade as a die set) are changed, this feeding mechanism must be readjusted'to give the proper feed for the new set of dies. This setting of the feeding mechanism is work which requires considerable time and care and the services of a skilled workman.

Ordinarily, the same die set would be used over and over again but not continuously. Short runs are common and necessitate frequent changes of dies. It will often be found necessary to remove one die set many times to allow others to be used in its place in the press. Thus, the feeding mechanism may have to be adjusted time and time again for any one die set,-that is each time it is replaced in the punch press. Much time is lost in setting the feeding mechanism, as will be clear, because a new adjustment of the feeding mechanism is required each time a die set is placed in the machine.

My invention has for its broad object the provision of a feeding mechanism which is attached lto the die set, as distinguished from the punch press or other machine, and remains with the die set, being removed with it from the machine. In this way, the feeding ymechanism needs to be adjusted just once for any given die set. Once set, the feeding mechanism requires no further adjustment because it is permanently attached to the die set and remains therewith at all times, being removed from and replaced in the machine with the die set to which it is fixed. Thus, a large saving in time can be effected by the use of my invention by eliminating the necessity for recurring adjustments of the feeding mechanism for any one die set.

The invention also has for an object to provide in a work feeding mechanism a specifically improved construction and arrangement of parts, as will more particularly appear lfrom the following detailed description and as will be pointed out in the appended claims.

The invention will be disclosed for illustrative purposes in connection with the accompanying drawings, in which:

Figs. 1 and 2 are top plan and front elevational views, respectively, of a work feeding mechanism embodying my invention, with the parts shown in retracted position;

Fig. 3 is an end elevational view thereof;

Figs. 4 and 5 are front and side elevational views, respectively, of one of the grippers, used either to feed the work or to hold the same against retrograde movement after it has been fed,-- these views being drawn to a larger scale to clearly show the detail;

Figs. 6 and 7 are top plan and front elevational views of the feeding mechanism, with the parts shown in advanced position; and

Fig. 8 is a cross sectional view taken on the line 8-8 of Fig. 6.

In these drawings, I have shown my invention as embodied in one type of die set, which may for example be used in a standard punch press. It will be clear, however, that the invention, according to its broad object, `is not limited to use with any special type of die set or to use in a punch press-the invention being applicable to feed stock to any machine in which there are a pair of cooperating and relatively movable members between which the stock is worked in any desired way, as for example by piercing, cutting, shaping or any combination of these operations.

Referring to Figs. 1 and 2, the die set, chosen by way of illustrative example as a setting or background for the invention, will be described. The cooperating and relatively movable members a and b are adapted for connection to the cooperating and relatively movable parts of a punch press. The member a is a punch holder and is provided with a shank c to t the ram r of the punch press. The member b is the die shoe and is adapted to rest on and be bolted to the bolster or bed p of the punch press. Usually, although not necessarily, there are guide pins, such as d, fixed in and upstanding from the stationary element b, which are slidably received in the movable member a. These members a and b may carry any desired kind of tools for working the metal or other kind of strip fed therebetween. As shown, there are punches e which are carried by the member a and cooperate with a die f carried by the member b to perforate the work; and a forming punch g carried by the member a, which cooperates with a pressure pad h, and the adjacent walls i on which it slides, to shape the work. The forming punch also has a shear edge 7', which operates to sever the forward end of the stock lcoincidentlly with the shaping of the same by the elements y, h and i. A portion of the usual operating rod for the pressure pad is shown at lc, such rod controlling the vertical movements of the pad h with respect to the walls z'. The die f has the'usual stripper plate Z, which holds the stock from rising during the retraction of the punches e following the perforation of the stock thereby. Openings m are provided in the die f and bolster b to allow the slugs or pieces of metal punched out by punches e to pass downwardly therethrough.

In this particular case the stock is a strip n of metal. In the rst instance this strip is advanced first beneath the punches e which perforate the stock on the down stroke of the ram of the press. On the next upstroke of the ram, the strip will be advanced by another measured length and the part perforated by punches e will be carried into position to be shaped and severed by the elements g, h, z' and j on the next downstroke of the ram. At the same time the punches e will perforate a section of the strip n which lies just to the left of the severed section.

The feeding mechanism of this invention includes a reciprocable member 10, operable on one stroke to grip the strip n and advance it a measured distance and operable on the other stroke vto move without causing movement of the strip n. This member 10 is mounted on a carriage 11 which is slidably mounted on ways 12, formed on a bracket 13, fixed to the bed b in any suitable way, as by the cap screws 14. The feeding means also includes a suitable actuating means for effecting reciprocation of the carriage 1l and in this case a cam 15 serves the purpose,-such cam being suitably xed as by the cap screws 16 to the member a. This cam serves by coaction with a roll 17, mounted on the carriage 11, as best shown in Fig. 8, to positively move the carriage to the left as viewed in Fig. 2. Such movement of the carriage also serves to stress a spring 18 which, when permitted by the cam, serves to move the carriage to the right and effect the advance stroke of the feeding member 10. The spring 18 is coiled around a rod 19, which at one end is xed as by the screw threads indicated, to an ear 20 on carriage 12. Rod 19, at its other end, is slidable in an ear 21 formed on the left hand end of the bracket 13. The last named end of rod 19 is threaded to receive a nut 22 and lock nut 23. These nuts are adjustable on rod 19 and the position of nut 22 on the rod controls the amount of the feeding movement of the carriage 11. As will be obvious, when cam 15 rises as shown in Fig. 7, the spring 18 will advance the carriage 12 until nut 22 abuts the ear 21. The cam 15 always moves the carriage back to a predetermined position being that shown in Fig. 1 wherein a vertical dwell surface 15 of the cam engages roll 17 and allows the member a'to descend and cause an operation to be performed on the strip n without moving the carriage. With the parts positioned as shown in Fig. 2, the feeding mechanism may be set in a very simple way by simply moving nut 22 on rod 19 until its right handface is spaced from the left hand face of ear 21 by a distance equal to the amount of feed desired. The nut 22 is then locked in this position by turning up the lock nut 23. Thus, the feeding mechanism is not only simple in construction but more important still, it is very simple and convenient to adjust. Moreover, it is easily adjusted with close accuracy and can be set to produce feeds from a minimum of 1/64 of an inch up to a maximum determined by the length of the cam, by increments as small as one one-thousandth of an inch if desired.

It will be seen from Fig. 2 that the cam 15 descends below the plane of the top of the bracket 13 and this bracket is cut away as indicated at 24 in Figs. 1 and 2, to provide the necessary clearance and permit the cam to descend the distance necessary for the tools e, g and y" to perform their work on strip n.

The feeding gripper 10 is mounted in a bracket comprising a horizontal base 25, a vertical wall 26 upturned therefrom, a vertically disposed lug 27 integral with and turned at right angles to the wall 26 and a horizontally disposed ear 28, integral with the lug 27 and bent forwardly from its upper edge to lie at right angles thereto. 'Ihe vertical wall 26 lies contiguous with a vertically upstanding web 29, forming part of the support for the described roll 17, as will be clear from Fig. 8. Wall 26 is secured by cap screws 30 or in any other suitable way to this web 29. This wall 26 also forms a guide for one edge of the strip n, as will be clear from Fig. 8. The strip n rides over the upper face of the base wall 25 and, to prevent the forward end of the strip from catching on the left hand edge of the base wall 25 when the strip is fed into the machine, such edge is bevelled as shown in Fig. 4. A cap screw 31 is threaded into the lug 27 and locked thereto by a nut 32, such screw being disposed horizontally in overlying relation with the base wall 25 and with its head 33 spaced a substantial distance from the lug. The gripper 10 has a vertically disposed sloil 34 therein, through which slot the body of screw 31 passes. At the upper end of this slot there are two laterally spaced lugs 35 formed on the gripper 10. The upper edge of the gripper is engaged by the lower end of a screw 36 threaded into the ear 28 and held in adjusted position by a lock nut 37. A conically formed coil spring 38 encompasses screw 31 with its end of small diameter abutting the head 33 of the screw' and its end of large diameter abutting the adjacent face of the gripper 10. The free end of the spring is engaged between the lugs, as best shown in Fig. 5, for the purpose of holding the spring from turning with the screw 3l whenever the latter( is turned. The largest end convolution of spring. 38 presses upwardly against the lugs 35 and tendslto hold the upper edge of the gripper engaged with the screw 36. The gripper is adjusted to lie in downwardly diverging relation with respect to the vertical wall 27, with its lower edge lying against the strip n and its upper edge engaged with the abutment screw 36 and the upper portion of its back face pressed against the vertical wall 27. It will be clear that when the gripper bracket is moved to the right as viewed in Fig. 4, the gripper 10 will tend to dig into the strip n and cause the latter to be moved forwardly with the bracket and the carriage 12 to which it is secured. Also, that when the bracket is moved to the left, the gripper will ride freely over the top of strip n without moving the same.

For convenience in manipulating the gripper by hand, as for example to release it and allow the strip to be fed forward by hand, a finger piece 40 is provided on one of the upper corners of the gripper. The screw 36 is adjustable to allow the gripper to be properly set to engage strips of various thicknesses.

For preventing retrograde movement of the strip n a holding device 41 of exactly the same properly located construction as the gripper 10 is provided. The device 41 is mounted in the same way as described, as will be clear from Fig. 2 but the supporting bracket is somewhat differently formed. The vertical wall 42 corresponds to the wall 27, above described, andV this wall 42 is integral with a right angularly disposed wall 43, which in turn is secured to a base wall 44, having a slotted extension 45, secured to the left hand end of bracket 13 by a bolt 46 at a location out of the path of the carriage 12. The strip n rides over and rests upon the base 44 and the gripper 41 cooperates with the strip n and base 44 in the same way as above described in connection with the gripper 10. The vertical wall 43 forms a guide for one edge of the strip n. Thus, as shown in Fig. l, the strip is guided between the two laterally spaced vertical walls 26 and 43. The gripper 41 allows the strip n to be fed forward beneath it by the gripper 10 but will dig into the strip and hold it from movement in a reverse direction. The slot in the extension 45 permits the gripper 41 and its associated guide 43 to be adjusted for strips of various widths.

The operation of the feeding mechanism will now be described. The grippers 10 and 41 are first adjusted for the thickness of strip to be used and the position of the guide wall 43 is so as to cooperate properly with the wall 26 in guiding the strip to the work forming tools. Then, with the parts positioned as in Fig. 2, the nuts 22 and 23 are adjusted on rod 19 to secure the desired length of feed. With these initial adjustments made, they need not thereafter be altered because the feeding mechanism is incorporated into the die set and always remains therewith, being removable with the die set from the punch press or other machine. Assuming that the parts are now positioned as in Fig. 2 and that the strip 1L overlies the various forming tools in the proper relation, as indicated, then when the member a descends further the punches e will perforate one section of strip n and the members g, h and i will bend into form another and previously perforated section of the strip and the last named section will be severed from the first named section by the shear edge j. Then as the member a rises, the roll 1'7 will eventually ride off the dwell surface l5' and onto the surface 15 of the cam, thereby releasing the carriage and allowing it to be moved forward under the force of the previously stressed spring 18. As the carriage moves to the right into the position shown in Fig. '7, the strip n will be advanced by another measured length by the gripper 10, thus bringing the previously perforated section of the strip n into position to be shaped by the tools g, h and i, and another section into proper relation with the die j to be operated on by the punches e. As the member a descends, the cam 15 acting on roll 17, will force the carriage to the left and again stress the driving spring 18, forcing the carriage back, durcarriage and compassing said rod and acting between said ing which action the gripper 10 rides freely over the upper face of the strip and the strip is held against return movement by the gripper 4l.

The invention has been disclosed herein, in an embodiment at present preferred for illustrative purposes, but the scope of the invention is defined by the appended claims rather than by the foregoing description.

What I claim is:

1; In a die set, a cam fixed to one of the two cooperating and relatively movable members of the set, a bracket havfng ways xed at one end to the other of said members, a carriage slidably mounted on said ways and having a part for engagement with said cam, a work gripping device mounted on the, carriage, an ear upstanding from the other end of said bracket, a rod paralleling said ways and fixed at one end to the sliding in said ear, a spring enear and carriage to move the latter in a direction opposite to that'in which the carriage is moved by said cam, and an adjustable abutment on said rod adapted to engage said ear and limit the extent of movement of the carriage by said spring.

2. In a die set, a cam xed to one of the two cooper-ating and relatively movable members of the set, a bracket having ways iixed at one end to the other of said members, a carriage slidably mounted on said ways and having a part for engagement with said cam, whereby the carriage may be moved in one direction, a work gripping device mounted on said carriage, resilient means acting on the carriage to move it in the opposite direction, a projection upstanding from said bracket, a rod xed to said carri-age in parallel relation with said ways and slidably engaged in said projection, and an adjustable abutment on said rod adapted to engage said projection and limit the extent of movement of the carriage by said resilient means.

3. In a die set, a bracket xed to one of the two cooperating and relatively movable members of the set, a carriage slidably mounted on said bracket for movement toward and away from said members, a work gripping device mounted on the carriage, a cam fixed to the other member of said set and having a surface for moving said carriage from a plurality of inner positions of adjustment outwardly away from said members and always into a predetermined position as said members are moved toward one another and having a dwell surface to hold said carriage in said position during continued movement of said members in said direction, resilient means for advancing the carriage to feed the Work between said members as said members move away from one another, and means for limiting the extent of work feeding movement of said carriage, said means being adjustable to vary the inner position to which said carriage will be moved by said resilient means.

HUBERT E. DICKERMAN. 

